Mig-35v2 is on left and Mig-29v4 is on the right.
I took out the Migv4 with straight vertical rudders like Scott's and inboard ailerons. It has the stock elevons. This plane is dialed in and a lot of fun. So I decided to experiment. It may have been an earlier post of Scott's, but somewhere I read about setting the CG. You climb at about 50% throttle nose up at 30 degrees and cut the throttle. The plane should continue climbing in a slow arc and then enter into a slow nose down descent. I did this repeatedly and kept pushing the battery towards the back. Bad habit from my fuelie days, but I've always flown nose heavy and I am kind of hardwired for that feel. The more I pushed the battery back, the more I felt like I was going to lose control but I didn't. The airplane felt much lighter? Not sure how to describe it.
As expected, vertical maneuvers were much easier and looked more natural and graceful. Not that my goal is to hover, but I did and was able to do a really nice tail slide. Rudder stall turns were easier as well. I've always dialed my planes to no trim at 50% throttle, I didn't check to see where this one would be with the Cg moved back. I am going to play around with this some more. The old sphincter got a little tight as I pushed her towards neutral CG COL, but wow what a new flight experience.
I also flew the Mig-35v2 with downsized wing and LERX. I swapped the FP from my F22. What an improvement over the Turnigy 2200. I need to work on dialing this plane in some more. I think I have the Cg too far forward. The plane weighs 3/4 oz more than the v4, but amazing the battery is way in the back for the same Cg. The tail plate cut out perhaps, not really sure why the difference. Here's a couple of picks. Once I get them both totally dialed in I'll measure the Cg as compared to stock. I'll measure the Cg from the nose of the plane to make it easier for us to compare--since I've changed the wing and LERX.
Hopefully weather will hold and I'll fly some more tomorrow. Once I dial the Mig-35v2 I'll do a video.
A la votre!
Stephan
Hey Stephan -
ReplyDeleteVery interesting results. I've never heard of trimming for CG in that method, will have to give it a try sometime. I normally just keep trimming and moving the battery around until I can get to zero trim and when I centralize the sticks the plane stays pretty much level.
I too like to fly certain planes a bit nose heavy, the F18 V3 and Su35 MK2 come to mind. This is primarily because if I don't, they continually want to zoom (not drastically, but they do want to climb) when I hit full throttle.
Any idea where your CG might have ended up in relation to where it is on the plans? When I was flying my Mig NAMCV2 the other day, I actually found I needed to push the battery forward about another 1/4" to keep the nose level, but it was one of the few days where I have flown in calm conditions as well.
With the battery moved back, did you find any issues with zooming at full throttle?
The Mig from my experience is one of the most forgiving planes WRT CG placement. When I first started playing with high alpha with the stock V4, I had moved the battery forward almost 3/4" before I needed any nose up trim to compensate in other parts of the flight envelope.
As I think back to the experiences I had with the V3, the CL and CG are quite different, at least the CG is. I seem to remember that my CG on the V3s was regularly at least 2+" behind where the wing breaks from the LERX and on my current NAMCV2 it is only about 1.25" behind that wing break. Unfortunately I don't have any V3s left around to measure that in relation to the rest of the plane.
Why I find that even more interesting is when I first flew the stock V4 and stock V3 together, the motor on the V4 is about 1" further forward than on the V3, leading one to believe then that the CG would be moved back somewhat to compensate for the forward movement of that weight, but the opposite seems to be true.
Makes me start to wonder if moving the CT (centre of thrust) then also impacts where CL and CG end up...? Another interesting thing to see with the Mig NAMCV3 with a shortened back end and motor moved another 1" forward from stock.
Great flight report as always, my friend. Tomorrow I should have some time to draw out the NAMCV3 mods on a set of Mig V4 plans, get some pictures taken and post them and the accompanying narrative so that pending my initial flight experiences they will be ready if you (or others) want to build one.
Cheers,
Scott